1、Designation:D437001(Reapproved 2012)Standard Test Methods forAcid and Base Milliequivalent Content of Electrocoat Bath1This standard is issued under the fixed designation D4370;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year
2、 of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 These test methods cover the determination of acid andbase milliequivalent contents of anodic and cathodic electro-coat
3、 baths and their ultrafiltrates.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of thi
4、s standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent Water3.Summary of Test Methods3.1 Specimens are titrated with standard acid and alkalisol
5、utions respectively.Alternative procedures are given fordetermining acid and base concentrations potentiometrically orusing a pH meter.4.Significance and Use4.1 The acid and base concentrations are a measurement ofthe titratable acidic and alkaline components in the electrocoatbaths.These measuremen
6、ts are used for research,production orelectrocoat bath process control.5.Apparatus5.1 Automatic Potentiometric Titrator with Stirrer andRecorder,any model.5.2 Analytical Balance,with sensitivity of 0.1 mg.5.3 pH Meter,any model.5.4 Glass and Saturated Calomel Electrodes.5.5 Syringes,5-mL disposable.
7、6.Reagents6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.Unless otherwise indicated,it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.3Other gr
8、ades may be used,provided it is ascertained that thereagent is of sufficiently high purity to permit its use withoutlessening the accuracy of the determination.6.2 Purity of WaterReferences to water shall be under-stood to mean water conforming to Type II of SpecificationD1193.6.3 Potassium Hydroxid
9、e Solution in Methanol,0.1NPrepare by dissolving 5.6 g of potassium hydroxide(KOH)pellets in 1 L of methanol.Standardize against NIST standardreference material of acid potassium phthalate No.84 using anautomatic potentiometric titrator4to a given end point or,alternatively,to a phenolphthalein end
10、point.6.4 Hydrochloric Acid Solution,0.1 NPrepare by mixingabout 8.50 mL of concentrated hydrochloric acid(HCl)(1.19sp gr)into a mixture of 600 mL water and 400 mL methanol.Standardize against 0.1 N potassium hydroxide solution(see6.3).6.5 1,3-Propanediol(Propylene Glycol)(PG).6.6 Tetrahydrofuran(TH
11、F).6.7 Reference pH Standard SolutionsCommercial stan-dards of pH 4.0,7.0,and 10.0.1These test methods are under the jurisdiction of ASTM Committee D01 onPaint and Related Coatings,Materials,and Applications and are the directresponsibility of Subcommittee D01.21 on Chemical Analysis of Paints and P
12、aintMaterials.Current edition approved June 1,2012.Published July 2012.Originally approvedin 1984.Last previous edition approved in 2006 as D4370 01(2006).DOI:10.1520/D4370-01R12.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For
13、 Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Reagent Chemicals,American Chemical Society Specifications,AmericanChemical Society,Washington,DC.For suggestions on the testing of reagents notlisted by the American Chemical Society,se
14、e Analar Standards for LaboratoryChemicals,BDH Ltd.,Poole,Dorset,U.K.,and the United States Pharmacopeiaand National Formulary,U.S.Pharmacopeial Convention,Inc.(USPC),Rockville,MD.4Svehla,G.,Automatic Potentiometric Titration,Pergamon Press,1978,p.187.Copyright ASTM International,100 Barr Harbor Dri
15、ve,PO Box C700,West Conshohocken,PA 19428-2959.United States1 7.Sampling and Sample Preparation7.1 The sample should be obtained while the electrocoatbath is under proper circulation such that a uniform material isobtained.In case of an ultrafiltrate,the material should bethoroughly mixed or stirred
16、 prior to sampling to assureuniformity.7.2 After sampling and prior to removing a test specimen,itis mandatory that the samples be shaken or stirred until they arehomogeneous and free of any settled material.This is particu-larly important if there is a delay between sampling the bathand performing the test.The absence of settled material can beascertained visually(in a transparent container)or by insertinga spatula,scraping the bottom of the container,and makingsure that there is no settled mat
